PCI Express (hereinafter called PCIe) is one type of an extended bus used in a computer and prescribed by PCI Special Interest Group (PCI-SIG). PCIe adopts a serial transfer interface and full duplex. Data transfer according to the PCIe is performed substantially like the transmission and reception of packet data (hereinafter merely called a packet) in a network and a transmission line of a packet is called PCIe link.
The PCIe includes Root complex, Endpoint and a PCIe switch as a component. The Root complex is a function for linking a CPU and a PCIe link. The Root complex is generally built in an I/O controller in a computer. The Endpoint is a function at an end of the PCIe link. The Endpoint is generally built in an I/O device.
The PCIe switch has a function for increasing the number of PCIe links and relaying a packet and is configured by plural PCI-PCI bridges. The PCI-PCI bridge has a function for determining whether a received packet is to be passed or not. The PCIe switch and the I/O device are connected via the PCIe link by Root Complex in the computer. The topology of PCIe components connected to Root Complex is called PCIe topology.
PCI Manager (hereinafter called PCIM) performs the management and the control of PCIe topology such as the generation, the deletion and a change of the PCIe topology. Since PCIM is installed as software, it can also be executed in a computer; however, the PCIM is generally installed in a supervisor processor (SVP) from a viewpoint of security. The PCIM gives a number called a bus number to respective PCIe links which the PCIM recognizes. In the PCIe, each PCIe link is identified using its bus number.
Further, the PCIM reads a number called a device number given beforehand from each PCI-PCI bridge and each I/O device which the PCIM respectively recognizes. In the PCIe, each PCI-PCI bridge and each I/O device are identified using their device numbers. For example, when a packet is transmitted to a certain I/O device, the packet can be correctly transmitted to a device which is a destination of the packet by adding the information of a bus number of a PCIe link connected to the I/O device and a device number of the I/O device to the destination of the packet.
As for routing control between an I/O device and a server using a data switch, technique that the data switch is connected to a proxy controller, a packet is classified into a packet for data transfer and a packet for control and the packet for control is processed in the proxy controller is disclosed in Patent Literature 1 for example. Further, access from at least one server to a virtual I/O device is described.
In addition, in Patent Literature 2 for example, technique that a module acquired by integrating a sorter of a packet and a built-in processor respectively called a configuration entity is built in a PCIe switch, a packet is classified into a packet for data transfer and a packet for control and the packet for control is processed in the built-in processor is disclosed.